The invention relates to a method for coding mailing items by means of applied, readable code signs. Information is nowadays applied by machine to mailing items during the automatic processing. This can occur by printing on a barcode (or other code) or by printing on clear text.
The printed-on information can:
Contain target information, meaning information on the recipient of the mail item, which is used, for example, for sorting; PA1 Contain an identification of the mail item, so that a later recognition is possible. Such an identification is frequently called an identification code (ID code) and is necessary, for example, for the offline processing; PA1 Contain information on the sender; PA1 Contain statistical and other information.
Combinations of two or more of the aforementioned types of information are also standard. Frequently, additional, redundant information is applied to reduce the risk of reading errors. At the same time, the printing technique and the reading technique must be as simple and inexpensive as possible, while the reading safety must be as high as possible. At the present time, the method that is easiest to use and at the same time relatively secure when using bar codes is the single-space printing of a fluorescent bar/no-bar code with a bar spacing of, for example, 1.5 mm.
The coding as well as the number of coded signs and the spacing between coded signs have until now been determined in that the codes, particularly the identification codes, for the most frequent mailing items with higher standard size are unambiguous and, if possible, fill the space provided for it.
If the mailing items also include items with a length shorter than the standard length, it can happen that the available space for the ID code may no longer be sufficient when maintaining the agreed-upon spacing between code signs. However reducing the size of the code signs and the spacing would result in higher reading and printing expenses as well as a reduction in the reading safety.
It is therefore the object of the invention specified in claim 1 to clearly code mailing items of varied size by maintaining the size and spacing between the coded signs selected for large mailing items.
It is possible to maintain the original size and the spacing between code signs despite the fact that the mailing items are smaller by measuring the area available for applying the code on the arriving mailing items, as well as by selecting and subsequently applying an unambiguous code with a code sign number that is adapted to the respectively determined surface for coding.
Several different methods can be used to determine the dimensions available for coding. Thus, the area not printed on and its dimensions are determined during the optical scanning of the surface of the mailing item at the agreed-upon location. In many cases, it is sufficient to determine or simply measure the length of the mailing item and reduce it by a fixed amount.
It is advantageous to reduce the existing redundant information in order to reduce the number of digits for an ID code. With smaller and in particular shorter items, which therefore have a reduced number of code signs, it is possible to check whether the ID code is unambiguous by keeping a statistic on the frequency of different lengths for items processed so far, which are available for the ID code and effect the number of signs to be applied. The unambiguous condition exists if for the observed time interval all accumulated mailing items with the ID code number adapted to the length can be clearly distinguished.
The invention is explained in the following with the aid of a drawing and exemplary embodiments.